1. Field of the Invention
This invention relates to lighting power control systems, more particularly to LED based lighting power control, and the control units for such systems.
2. Description of the Related Art
Display units, such as shelving units, refrigeration units, and freezer units, are commonly used in retail applications to display merchandise. To enhance the visibility of merchandise within these units, different types of lighting are incorporated. Various types of lighting systems are used with different light sources such as incandescent bulbs or fluorescent tubes. One of the problems associated with the conventional lighting units and systems is that their light sources can experience relatively short lifespans and they can have relatively low electrical efficiency. Incandescent bulbs and fluorescent tubes have a relatively short lifespan, particularly when compared to other light sources such as typical light emitting diodes. Also, heat produced by fluorescent lights inside cooled areas or display cases which are refrigerated place an additional load on the cooling or refrigeration systems. These light sources are also electrically inefficient and providing sufficient lighting, especially in large lighting applications, requires the consumption of significant energy. For example, a standard fluorescent tube 60 inches in length consumes as much as 60 to 70 watts, and conventional display units can utilize many of these tubes.
Alternative light sources have also been used in display units, including light emitting diodes. However, many of these designs result in only minimal energy saving, and often produce non-uniform lighting, secondary spotting or “glare” effects. Furthermore, the power supplies and power units associated with these systems do not allow for adjustable control of power consumption. That is, these conventional systems do not have a mechanism to allow power consumption to be adjusted based on current ambient conditions and light source applications.